Approximately 6,000,000 orthotic devices are sold annually in the U.S. to the many people, including one of the inventors of the present application, suffer from drop foot, a neural disorder in which one cannot dorsiflex, or raise up, the toes or raise the foot from the ankle. As a result, the foot is stuck in a plantar flexed (hanging) position and drags on the ground when walking. This condition can be caused by: stroke, ALS, muscular dystrophy, multiple sclerosis, cerebral palsy, bone sarcoma, and aplastic paraplegia.
A person with drop foot may employ one or more of the following strategies while walking to avoid the foot from dragging on the ground: bending the knee of the affected leg, lifting the hip to swing the leg forward, and swinging the leg outward. Such gaits result in fatigue, misalignment of the spine and neck, and increased falling incidents, as well as calling unwanted attention to the person with such a gait.
Persons suffering from drop foot commonly suffer from neuropathy, a pins-and-needles sensation along with hypersensitivity to modest stimuli, such as the rubbing associated with donning a shoe.
Many people with drop foot wear an ankle-foot orthotic (AFO) to provide a more natural gait. Prior art AFOs are strapped to the leg and then inserted into a shoe to physically manipulate the ankle to dorsiflex. Because the AFO is bulky, users buy a shoe of a size larger than they would normally wear without the orthotic. If only one of the patient's feet has drop foot, two pairs of shoes are purchased, one for the foot wearing the orthotic and the normal size for the unaffected foot. The AFO interferes with typical shoes in one or more spots which necessitate cutting the shoe back to make it fit. A custom orthotic costs in excess of $1000, lasts from 6 months to 3 years, causes many wearers to buy 2 pairs of shoes to accommodate the AFO on one foot, and the shoe into which the AFO is fitted is further compromised by cutting it back, thereby reducing the normal life of the shoe and further making the wearer's condition more conspicuous. This represents a significant cost to AFO wearers with a limited period of satisfactory performance of their shoe/orthotic system.
Depending on the condition and the severity that leads to drop foot, many of those suffering from it are unable to self-dress, particularly to reach the end of an extremity like the leg to pull on a shoe. Adding the complication of putting a foot with an orthotic attached into a shoe exacerbates the situation. Having an AFO that allows such persons to dress independently is a desirable goal.
For AFO wearers suffering from neuropathy, having AFO pushing against the foot to cause the foot to move in a desired way causes rubbing with the foot. There is some rubbing between foot and shoe while walking for anyone. However, with an AFO attached to one's leg(s) and that AFO having hard surface can lead to excruciating pain for some.
Another problem with the state of the art is that people who suffer from drop foot have difficulty sliding their foot into a shoe. The toes curl under and difficult to uncurl. Some people with neuropathy may not notice until they experience pain while walking.